Study of Plastic Explosives based on Attractive Cyclic Nitramines,Part II. Detonation Characteristics of Explosives with Polyfluorinated Binders

A series of plastic bonded explosives (PBXs) based on Viton A and Fluorel binders were prepared using four nitramines, namely RDX (1,3,5‐trinitro‐1,3,5‐triazinane), β‐HMX (β‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocane), BCHMX (cis‐1,3,4,6‐tetranitro‐octahydroimidazo‐[4,5‐d]imidazole), and ε‐HNIW (ε‐2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane). The detonation velocities, D, were determined. Detonation parameters were also calculated by means of modified Kamlet & Jacobs method, CHEETAH and EXPLO5 codes. In accordance with our expectations BCHMX based PBXs performed better than RDX based ones. The Urizar coefficient for Fuorel binder was also calculated.     

Crystallography and Structure–Property Relationships of 2,2″,4,4′,4″,6,6′,6″‐Octanitro‐1,1′ : 3′,1″‐Terphenyl (ONT)

An X‐ray crystallographic study of 2,2″,4,4′,4″,6,6′,6″‐octanitro‐1,1′ : 3′,1″‐terphenyl (ONT) has been carried out. The dihedral angles between benzene rings vary from 84.9° to 89.4°. Nonbinding interatomic distances of oxygen atoms inside all the nitro groups are shorter than the intermolecular contact radii for oxygen. On the basis of the DFT B3LYP/6‐31(d, p) method it was found that the difference between the X‐ray structure in the solid phase and DFT result for the gas phase is 98 kJ mol⁻¹, and the bearer of the highest initiation reactivity of the ONT molecule in the solid phase should be the nitro group at 4″‐position, in contrast to those at 4′‐ or 6′‐position that play this role in the isolated molecule. It has been stated that the nitro groups at the reaction centers of the ONT molecule are relatively well specified by their ¹⁵N NMR chemical shifts.     

高热稳定性多硝基芳烃的研究

The paper is focused on 2,4,6,4′,6′,2″,4″,6″-octanitro[1,1′,3′,1″]-terphenyl (ONT), 2,2′,2″,4,4′,4″,6,6′,6″-nonanitro[1,1′,3′,1″]-terphenyl (NONA), 2,4,6-tris(2,4,6-trinitrophenyl)-1,3,5-triazine (TPT), N,N-bis(2,4-dinitrophenyl)-2,4,6-trinitroaniline (NTFA), 2,2′,4,4′,6,6′-hexanitrobiphenyl (HNB), 1,3-dinitrobenzene (1,3-DNB) and 1,3,5-trinitrobenzene (TNB). The initiation reactivity of these substances has been studied by means of the data obtained from non-isothermal differential thermal analysis (DTA), their ignition temperatures, impact sensitivity, the data obtained from the Russian manometric method and the detonation characteristics. For comparison, also the data published about 2,2′,2″,2″′,4,4′,4″,4″′,6,6′,6″,6″′-dodecanitro-[1,3′,1′,1″]quaterphenyl (DODECA) have been included. The paper specifies and discusses the relationships between the results of various methods used, inclusive of the forms of modified Evans-Polanyi-Semenov relationship. It has been stated that the technologically most attractive substances, out of those studied, can be ordered in the sequence ONT-TPT-NONA-NTFA according to their increasing thermal reactivity.     

A New View of Relationships of the N–N Bond Dissociation Energies of Cyclic Nitramines. Part III. Relationship with Detonation Velocity

The values of bond dissociation energies, BDE, of the weakest N–N bonds and total energies, E_total, of molecules have been calculated for 14 cyclic nitramines by means of the UB3LYP/6-31G? and UB3LYP/6-31+G? // PM3 methods. Ambiguous relationships were found between the logarithms of detonation velocities and BDE/E_total ratios of these nitramines. The reason of this found ambiguity mainly lies in a real conformation of the respective molecules and intermolecular force effects in real molecular crystals, which are included in neither of the two calculation methods. However, partial relationships of this type can be used for evaluation of effectiveness of the method of designing molecular structures of energetic cyclic nitramines for obtaining products with the maximum possible performance.     

Detonation Performance of TATP/AN‐Based Explosives

The detonation velocity and performance were determined for four mixtures of triacetone triperoxide (3,3,6,6,9,9‐hexamethyl‐1,2,4,5,7,8‐hexoxonane, TATP), ammonium nitrate (AN) and water (W) by cylinder expansion tests. The composition of these mixtures varied in the following ranges: 21–31% TATP, 37–54% AN and 19–32% W. The obtained results were compared with those of powdery 2,4,6‐trinitrotoluene (TNT), AN‐fuel oil explosive (ANFO) and emulsion explosive. It was found that the tested TATP/AN/W mixtures represent typical non‐ideal explosives with relatively low critical diameter and with high sensitivity to initiation despite the high content of water due to the presence of the primary explosive (TATP). The detonation velocity is comparable to that of powdery TNT (at similar density). However, the acceleration ability is significantly lower than that of powdery TNT.     

以环状硝胺为基的几种塑料黏结炸药的初步研究

用聚异丁烯(PIB),丙烯腈-聚丁橡胶(ABR),维通A黏结剂和RDX,HMX,BCHMX和ε-HNIW四种硝胺炸药制备了一系列塑性炸药.PETN和以PETN为基的三种塑性炸药用于比较.测试了这些炸药的爆速,撞击和摩擦感度.摩擦感度与撞击感度的关系以及两种感度与D<'2>的关系表明摩擦力向硝胺炸药分子反应中心的转移机理...     

Friction Sensitivity of Nitramines. Part Ⅳ: Links to Surface Electrostatic Potentials（英）

The friction sensitivity (FS) of five aliphatic linear and eight cyclic nitramines has been determined and correlated with DFT B3LYP/6-31-G(d,p) // 6-311 + G(d,p) positive ( VS,max ) and negative ( VS,...     

Impact Sensitivity in Respect of the Crystal Lattice Free Volume and the Characteristics of Plasticity of Some Nitramine Explosives（英）

The relationship between the crystal lattice free volume,ΔV,and impact sensitivity,E_(dr),of ten nitramines has been analyzed. It was found that this relationship is not uniquely determined,i. e. it is not given only by their own ΔV values but fundamentally by the type and intensity of the intermolecular forces in the nitramine crystals. Also,relationships between the E_(dr)values,on the one hand,and bulk modulus,K,and shear modulus,G,on the other,have been the subject of discussion not only for pure cyclic nitramines but also for their PBXs,bonded by a poly-fluoro binder. The closest linear correlation exists between the E_(dr)values and dimensionless K·G~(-1) ratio which indicates the plasticity range. A similar relationship is valid also for the ΔV values. Relationships of the E_(dr) and / or ΔV values with the shear modulus or to the K·G~(-1) ratio reflect an unusual behavior of ε-HNIW to which the published morphological instability of this particular HNIW version might also be related.     

干燥温度对聚合物膜多孔结构影响的测定方法

着重介绍了一种新的方法讨论聚合物膜干燥温度对多孔结构的影响。在膜干燥过程中,升温使膜对氢的静态渗透速率降低,表现出膜的孔率减小。